1. Field of the Invention
This invention relates to optical data storage and more particularly relates to converting between serial data and encoded holographic data.
2. Description of the Related Art
Advances in optical data storage systems are rapidly increasing data storage capacity. For example, with the holographic data storage systems available from InPhase Technologies™ up to 150 GB of data storage space is available on a holographic medium the size of a Compact Disk (“CD”). That capacity adds up to nearly 200 times the traditional data storage capacity of the CD.
Prior Art FIG. 1A illustrates one a hologram recording device. A typical holographic recording device includes a laser light source 102, a laser splitter 104, and a resultant data carrier beam 106 and reference beam 108. The apparatus may additionally include a Spatial Light Modulator (“SLM”) 112, a mirror 116, and a holographic data storage medium 122.
Generally, the SLM 112 is an LCD type device. Data is represented by either a light or a dark pixel on the SLM 112 display. The SLM 112 is typically translucent. Laser light originating from the laser source 102 is split by the beam splitter 104 into two beams, a carrier beam 106 and a reference beam 108. The carrier beam 106 picks up the image 110 displayed by the SLM 112 as the light passes through the SLM 112. The result is a propagating image 114. The reference beam 108 is reflected by the mirror 116 into the path of the propagating image 114. When the reflected reference beam 118 interferes with the propagating image 114, a hologram 120 is formed. The resulting hologram 120 may be stored on a holographic storage medium 122.
Prior Art FIG. 1B illustrates a hologram reading device. The reading device includes the same laser light source 102, beam splitter 104, and holographic storage medium 122. Additionally, an optical sensor 126 is positioned a distance away from the holographic storage medium 122 sufficient to accurately capture the image 124 projected. To read the hologram, only the reflected reference beam 118 is incident on the holographic storage medium 122. As the reference beam 118 interferes with the hologram stored on the storage medium 122, an image 124 resembling the original image 110 displayed by the SLM 112 is projected against the optical sensor 126. The optical sensor 126 then captures the data.
An additional feature of currently available holographic storage devices is the rate at which data may be written to and read from the medium. In holographic storage systems, the data is stored as a planar optical image. Each medium may contain several images, and each image is capable of storing several megabytes of data. In such systems, each image is-written to the medium and read from the medium with a single flash of laser light. Consequently, several megabytes of data may be written to the medium or read from the medium with a single pulse of light.
While these new advances solve some capacity and size issues, some common issues have still not been resolved. For example, critical data must still be stored redundantly, and corrupt or lost data must still be recovered in some way. Holographic storage systems may contain more data and store that data more quickly, however the common tasks of creating backup copies, performing data recovery operations, and the like must still be considered.
Typical data backup solutions are often cumbersome, costly, and inefficient. As Most backup solutions require procuring and configuring a second storage device for each storage device utilized. These second storage devices contain a backup copy of the data stored on the primary storage device. These backup devices are expensive, require considerable time to configure and maintain, and severely tax system and network bandwidth resources in continually creating and updating the backup copies of the data.
For example, a typical data storage system utilizing magnetic hard disks may include an array of four disks. For redundancy, each of the four disks must have an associated backup disk. Up front, the cost of the system is doubled to gain the benefits of redundancy. Furthermore, a system administrator must configure the backup disks to mirror the data on the primary storage disks, or create a backup and update process. The added network bandwidth required to continually create and update the backup copies of the data may require more bandwidth, leaving less bandwidth for the system users and other operations required to administer the storage system and associated networks.
Although holographic data storage systems may improve data read and write rates, and provide additional space for backup copies, the issue of reliability and redundancy still remains. What is needed is a data storage solution that maintains the integrity of data, provides data recovery capabilities, and maintains high storage capacities and rapid read data access rates, without requiring procurement and configuration of multiple sets of hardware components, and without negatively impacting network bandwidth usage.
From the foregoing discussion, it should be apparent that a need exists for an apparatus, system, and method for converting between serial data and encoded holographic data. Beneficially, such an apparatus, system, and method would encode backup information directly with the data as it is written to the storage medium, and make use of the high data access rates available with current holographic storage mediums such that data access rates would not be perceivably impacted. Additionally, network bandwidth utilization for backup copy creation and updates would be eliminated.